1. Field of the Invention
The present invention relates to a method of processing and transferring vehicle body members with a robot, in which the vehicle body members are processed with a processing device attached to the robot and then transferred to be carried into a work station for a successive processing with a holding device attached to the robot in place of the processing device.
2. Description of the Prior Art
In a vehicle body assembly line, various kinds of work are carried out with robots for the purpose of mechanizing or automatizing processes of assembling vehicle bodies. In this connection, there has been proposed, in the case of assembling a body panel member with a plurality of subdivided components, to use a robot for transferring the subdivided body panel components to a work receiving base and for welding the subdivided body panel components transferred to the work receiving base to together so as to constitute the body panel member, as disclosed in, for example, the Japanese patent application published before examination under publication number 60-118391.
In a previously proposed vehicle body assembly line in which a robot used for transferring and welding subdivided body panel components constituting a body panel member, as shown in FIG. 1, a robot 1 is installed between two work stations ST.sub.1 and ST.sub.2, at each of which the body panel member is subjected to a predetermined work, and a panel welding table 2 is disposed in the vicinity of the robot 1. A body side panel member 3 which is constituted with a plurality of subdivided body panel components is placed on the panel welding table 2.
The robot 1 is operative first to move an end portion of an arm 1a thereof into a welding gun holder 5 and a resistance welding gun 6 having been held by the welding gun holder 5 is removed from the welding gun holder 5 to be attached to the end portion of the arm 1a of the robot 1. The resistance welding gun 6 attached to the end portion of the arm 1a of the robot 1 is moved by the robot 1 to be put on the body side panel member 3 placed on the panel welding table 2 and operative to provide resistance welding at each of portions of the body side panel member 3 which is to be welded. After the resistance welding, the resistance welding gun 6 is moved by the robot 1 into the welding gun holder 5 and removed from the end portion of the arm 1a of the robot 1 to be held by the welding gun holder 5.
The robot 1 is further operative to move the end portion of the arm la into a panel holder supporting portion 7 and a panel holder 8 having been supported by the panel holder supporting portion 7 is removed from the panel holder supporting potion 7 to be attached to the end portion of the arm 1a of the robot 1. The panel holder 8 attached to the end portion of the arm 1a of the robot 1 is caused to engage with the body side panel member 3 placed on the panel welding table 2 and having been welded so as to hold the same.
Then, the robot 1 is operative to transfer the body side panel member 3 held by the panel holder 8 which is attached to the end portion of the arm 1a of the robot 1 to a panel carrier 9 which is provided for conveying the body side panel member 3 into and out of the work station ST.sub.1 wherein the body side panel member 3 is subjected to finish processing. The panel holder 8 is caused to release the body side panel member 3 to put the same on the panel carrier 9 and the body side panel member 3 is conveyed into the work station ST.sub.1 by the panel carrier 9. After that, the panel holder 8 is moved by the robot 1 into the panel holder supporting portion 7 and removed from the end portion of the arm 1a of the robot 1 to be supported by the panel holder supporting portion 7.
Next, the robot 1 is operative again to move the end portion of the arm 1a into the welding gun holder 5 and the resistance welding gun 6 having been held by the welding gun holder 5 is removed from the welding gun holder 5 to be attached to the end portion of the arm 1a of the robot 1. The resistance welding gun 6 attached to the end portion of the arm 1a of the robot 1 is moved by the robot 1 to be put on a body side panel member 3 placed newly on the panel welding table 2 and operative to provide resistance welding at each of portions of the new body side panel member 3 which is to be welded. Within the duration of such resistance welding, the finish processing for the body side panel member 3 in the work station ST.sub.1 is completed and the body side panel member 3 having been projected to finish processing is conveyed out of the work station ST.sub.1 by the panel carrier 9.
After the resistance welding on the new body side panel member 3, the resistance welding gun 6 is moved again by the robot into the welding gun holder 5 and removed from the end portion of the arm 1a of the robot 1 to be held by the welding gun holder 5.
The robot 1 is operative again to move the end portion of the arm 1a into the panel holder supporting portion 7 and the panel holder 8 having been supported by the panel holder supporting portion 7 is removed from the panel holder supporting potion 7 to be attached to the end portion of the arm 1a of the robot 1. The panel holder 8 attached to the end portion of the arm 1a of the robot 1 is caused to engage with the body side panel member 3 placed on the panel carrier 9 and having been conveyed out of the work station ST.sub.1 so as to hold the same.
Then, the robot 1 is operative to transfer the body side panel member 3 held by the panel holder 8 to a panel carrier 10 which is provided for conveying the body side panel member 3 into the work station ST.sub.2 wherein the body side panel member 3 having been subjected to finish processing is arranged for being incorporated with another vehicle body member. The panel holder 8 is caused to release the body side panel member 3 to put the same on the panel carrier 10 and the body side panel member 3 is conveyed into the work station ST.sub.2 by the panel carrier 10. Then, the panel holder 8 attached to the end portion of the arm 1a of the robot 1 is caused by the robot 1 to engage with the body side panel member 3 placed on the panel welding table 2 and having been welded so as to hold the same.
The robot 1 is further operative to transfer the body side panel member 3 held by the panel holder 8 to the panel carrier 9 provided for conveying the body side panel member 3 into and out of the work station ST.sub.1. The panel holder 8 is caused to release the body side panel member 3 to put the same on the panel carrier 9 and the body side panel member 3 is conveyed into the work station ST.sub.1 by the panel carrier 9. Then, the panel holder 8 is moved by the robot 1 into the panel holder supporting portion 7 and removed from the end portion of the arm 1a of the robot 1 to be supported by the panel holder supporting portion 7.
After that, the robot 1 starts the next cycle of operation with moving the end portion of the arm 1a into the welding gun holder 5 so that the resistance welding gun 6 is removed from the welding gun holder 5 to be attached to the end portion of the arm 1a of the robot 1 and repeats the above described operations successively.
In the case where the resistance welding on the body side panel member 3 and the transfer of the body side panel member 3 having been subjected to the resistance welding are carried out with the robot 1 provided in common as aforementioned, whenever the operation of the robot 1 is switched from the resistance welding on the body side panel member 3 to the transfer of the body side panel member 3 having been subjected to the resistance welding or vice versa, the resistance welding gun 6 is removed from the end portion of the arm 1a of the robot 1 to be held by the welding gun holder 5 and then the panel holder 8 is removed from the panel holder supporting portion 7 to be attached to the end portion of the arm 1a of the robot 1, or the panel holder 8 is removed from the end portion of the arm 1a of the robot 1 to be supported by the panel holder supporting portion 7 and then the resistance welding gun 6 is removed from the welding gun holder 5 holder to be attached to the end portion of the arm 1a of the robot 1. This results in that a relatively long time is spent for each change between the resistance welding gun 6 and the panel holder 8 in relation to the end portion of the arm 1a of the robot 1 and therefore the robot 1 is put in such a situation as to be compelled to operate with undesirably low working efficiency.